Link found between obesity, gut bacteria and genes

18 June 2010

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Researchers at the University of Maryland School of Medicine
have found a link between obesity, a variant of the FTO gene and the
presence of certain bacterial groups in the digestive tract.

“Work currently under way suggests that an interaction between
genetic factors and the composition of the bacteria that inhabit the
human gut may predispose certain individuals toward obesity,” said
Margaret Zupancic, PhD, a research fellow with the Institute for
Genome Sciences at the School, who presented one of the studies.

"These results potentially provide insight into the mechanisms by
which genetics may predispose some people to obesity. They could
also help pave the way toward a future in which genetic screening in
conjunction with individually tailored treatments could help people
at risk for obesity to maintain a healthy weight."

Zupancic and her colleagues analyzed the gut bacterial
communities of lean and obese individuals in the Old Order Amish of
Lancaster County, Pennsylvania, which has a relatively homogenous
population in regard to both genetics and lifestyle. Initially the
researchers found no correlation between the composition of the gut
bacteria and obesity, but when they factored in the genetic makeup
of the participants, certain patterns began to emerge.

One pattern was a statistically significant correlation between
whether the participant carried a given variant of a gene called FTO
associated with obesity and the presence of certain bacterial groups
in the digestive tract.

The researchers also found that in people with certain genetic
variations in taste receptor genes, a low level of bacterial
diversity in the gut correlated with a higher likelihood of obesity,
while a high level of bacterial diversity correlated with a lower
likelihood of obesity.

“While this work is still at a relatively early stage, results
such as these could lead to applications such as probiotic
[stimulate beneficial bacteria] or antibiotic-based treatments for
obesity that could be individualized based on a person’s unique
genetic and gut microbial makeup,” says Zupancic.